The apparatus for determining a subject as a forged finger when the color of the image acquired by reflecting visible light of forgery-determining illumination on the subject does not coincide with that of the finger image that has been acquired likewise and has been previously registered in a data storing means is described in Patent literature 1. The same apparatus collates a characteristic point obtained from the transmitted light by radiating near-infrared ray of individual identification illumination to the finger with the characteristic point of the finger image that has been acquired likewise and has been previously registered into the data storing means, and performs the individual identification.
The apparatus for selectively switching white light and infrared light, reflecting the white light on a surface layer portion of the finger thereby to acquire the fingerprint image, making the infrared ray incident inside the finger and scattering the infrared ray thereby to acquire a vein image, comparing the fingerprint image and the vein image with the registered fingerprint image and the registered vein image, respectively, and authenticating a specific personal is described in Patent literature 2.
The apparatus for comparing the fingerprint image with high sensitivity with the fingerprint image with low sensitivity, and determining the forged finger is described in Patent literature 3.
The apparatus for, based on a difference of the finger vein images imaged with the transmitted lights having a different wavelength, determining whether the above finger vein image is the finger vein image of a living body is described in Patent literature 4.
On the other hand, the technique of using a prism as a scanner for the fingerprint authentication, and augmenting a contrast is described in Patent literature 5.